能量密度对选区激光熔化纯钨致密度及组织性能的影响
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摘要
难熔金属由于其具有熔点高、蒸汽压低、高温强度高等特性,在武器装备、通讯、医疗等领域具有广泛应用。纯钨的选区激光熔化打印,可解决难熔金属传统粉末冶金在复杂形状和超细晶粒方面面临的难题。本文研究了激光能量密度对纯钨致密度、硬度及显微组织的影响。结果表明,随激光能量密度增大,致密度和显微硬度逐渐增大。最大致密度可达75%,显微硬度达到485 HV,远远高于传统粉末冶金的方法(260 HV)。打印后的显微组织为较细的等轴晶,晶粒尺寸小于1μm。
Some refractory metals are widely used in the fields of weaponry,communication and medical fields due to their high melting point,low steam pressure and excellent high temperature strength.Using selective laser melting(SLM)technique to print pure tungsten can solve the problems of traditional powder metallurgy technology for some complicated shapes and ultra-fine grains.The effects of energy density of SLM on the density,hardness and microstructure of the pure tungsten were studied.The results show that the density and microhardness increase with the increase of volumetric energy density(VED).The maximum relative density can reach 75%,and the microhardness reaches 485 HV,far more than traditional powder metallurgy(260 HV).The microstructure after SLM is a fine equiaxed grain with the grain size less than 1μm.
Some refractory metals are widely used in the fields of weaponry,communication and medical fields due to their high melting point,low steam pressure and excellent high temperature strength.Using selective laser melting(SLM)technique to print pure tungsten can solve the problems of traditional powder metallurgy technology for some complicated shapes and ultra-fine grains.The effects of energy density of SLM on the density,hardness and microstructure of the pure tungsten were studied.The results show that the density and microhardness increase with the increase of volumetric energy density(VED).The maximum relative density can reach 75%,and the microhardness reaches 485 HV,far more than traditional powder metallurgy(260 HV).The microstructure after SLM is a fine equiaxed grain with the grain size less than 1μm.
引文
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[2]FAN J L,GONG X,HUANG B Y,et al.Densification behavior of nanocrystalline W-Ni-Fe composite powders prepared by sol-spray drying and hydrogen reduction process[J].Journal of Alloys and Compounds,2010,489(1):188-194.
[3]SHEN Q,ZHOU D,ZHANG J,et al.Study on preparation and property of porous tungsten via tape-casting[J].International Journal of Refractory Metals&Hard Materials,2017,69:27-30.
[4]杨广宇,汤慧萍,刘楠,等.增材制造技术制备钨材料研究进展[J].热加工工艺,2016,24:16-18.YANG Guangyu,TANG Huiping,LIU Nan,et al.Research progress in preparation of tungsten materials by additive manufacturing technology[J].Hot Working Technology,2016,24:16-18.
[5]GU D,JIA Q.Novel crystal growth of in situ wc in selective laser-melted W-C-Ni ternary system[J].Journal of the American Ceramic Society,2014,97(3):684-687.
[6]FAHIM N F.Thermal conductivity of plasma-sprayed W/SiCcomposite for high-temperature energy applications[J].Surface&Coatings Technology,2008,202(9):1696-1703.
[7]XIA M,YAN Q,XU L,et al.Bulk tungsten with uniformly,dispersed La2O3 nanoparticles sintered from co-precipitated La2O3/W nanoparticles[J].Journal of Nuclear Materials,2013,434(1/3):85-89.
[8]CHEN H,GU D,XIONG J,et al.Improving additive manufacturing processability of hard-to-process overhanging structure by selective laser melting[J].Journal of Materials Processing Technology,2017,250:99-108.
[9]LI R,WANG M,YUAN T,et al.Selective laser melting of a novel Sc and Zr modified Al-6.2Mg alloy:processing,microstructure,and properties[J].Powder Technology,2017,319:117-128.
[10]LI R,NIU P,YUAN T,et al.Selective laser melting of an equiatomic CoCrFeMnNi high-entropy alloy:processability,non-equilibrium microstructure and mechanical property[J].Journal of Alloys and Compounds,2018,746:125-134.
[11]ZHOU L,YUAN T,LI R,et al.Microstructure and mechanical properties of selective laser melted biomaterial Ti-13Nb-13Zr compared to hot-forging[J].Materials Science and Engineering:A,2018,725:329-340.
[12]ZHOU L,YUAN T,LI R,et al.Selective laser melting of pure tantalum:densification,microstructure and mechanical behaviors[J].Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing,2017,707:443-451.
[13]KRUTH J P,LEVY G,KLOCKE F,et al.Consolidation phenomena in laser and powder-bed based layered manufacturing[J].Cirp Annals-Manufacturing Technology,2007,56(2):730-759.
[14]ZARCA G,ORTIZ I,URTIAGA A,et al.Modelling the physical properties of ionic liquid/metal salt mixtures with the soft-SAFT equation of state:application to carbon monoxide reactive separation[J].Computer Aided Chemical Engineering,2017,40:217-222.
[15]KRUTH J P,MERCELIS P,VAN VAERENBERGH J,et al.Binding mechanisms in selective laser sintering and selective laser melting[J].Rapid Prototyping Journal,2005,11:26-36.